Agricultural vehicle

ABSTRACT

A ground vehicle having an implement attached at one end of the vehicle for pivotal movement relative to the ground. The implement may be a swather table or the like which is equipped with a pair of power activated lift cylinders for selective raising or lowering of the swather table. The lift cylinders are interconnected between the swather table and one end of a rocker arm which is pivoted to the frame of the vehicle. A pair of counterbalancing springs are co-operatively positioned relative to the lift cylinders and have one end attached to the frame of the vehicle and the other end of the pivotal rocker arm. The upper end of the swather table is supported for pivotal fore and aft movement on a transverse crossbar which is rotatable in the frame of the vehicle. The outer ends of the table-supporting crossbar are each connected to an interconnected lift arm and lever assembly for rotation of the crossbar within the frame upon respective pivotal movement of the swather table. The transverse cross bar defines a torsion rod adapted to maintain the table in level position, and one of the lift arm and lever assemblies is provided with adjusting means for adjustment of the torque characteristic of the torsion spring.

United States Patent 1 Twidale et al.

[ Apr. 17, 1973 AGRICULTURAL VEHICLE [75] Inventors: William H. Twidale,lslington, On-

tario; Mark K. Byrnes, Mississauga, Ontario, both of Canada [73]Assignee: Massey-Ferguson Industries Limited, Toronto, Ontario, Canada221 Filedt Nov. 26, 1971 21 Appl.No.: 202,214

Primary ExaminerLouis G. Mancene Assistant Examiner-J. A. OliffAttorney-Robert L. Farris 5 7 ABSTRACT A ground vehicle having animplement attached at one end of the vehicle for pivotal movementrelative to the ground. The implement may be a swather table or the likewhich is equipped with a pair of power activated lift cylinders forselective raising or lowering of the swather table. 'The lift cylindersare interconnected between the swather table and one end of a rocker armwhich is pivoted to the frame of the vehicle. A pair of counterbalancingsprings are co-operatively positioned relative to thevlift cylinders andhave one end attached to the frame of the vehicle and the other end ofthe pivotal rocker arm. The upper end of the swather table is supportedfor pivotal fore and aft movement on a transverse crossbar which isrotatable in the frame of the vehicle. The outer ends of thetable-supporting crossbar are each connected to an interconnected liftarm and lever assembly for rotation of the crossbar within the frameupon respective pivotal movement of the swather table. The transversecross bar defines a torsion rod adapted to maintain the table in levelposition, and one of the lift arm and lever assemblies is provided withadjusting means for adjustment of the torque characteristic of thetorsion spring.

12 claims, 7 Drawing Figures- PATENIEUAFRYYIUYS 3.727, 385

SHEET 1 [IF 3 INVENTORS.

WILLIAM H. TWIDALE BY MARK K.BYRNE5 mam Msiiw ATTORNEY-5.

INVENTORS.

sum 2 BF 3 PATENTEUAFR mm E m w W d Tm r T H8 A K M mm WM MW Y. B

PATENTEI] APR I 7 I973 SHEET 3 [IF 3 INVENTORS, WILLIAM H. TWIDALE BYMARK K. BYRN AAIMII,

ATTORNEYS.

AGRICULTURAL VEHICLE The present invention relates in general toagricul- 1 tural machines and more in particular to a harvesting machineof the swather type which is equipped with a pivotally movable platformor table assembly and to an sembly.

As is known, conventional harvesting machines of the swather type have aplatform or table assembly in fore or aft position of the machine whichis equipped with the usual crop handling mechanisms to cut standing cropfor deposit in windrows behind the machine.

Typically, the platform or table assembly of the harvester supports avariety of driven devices, such as crop 7 cutting mechanisms, pick-upreels, bat reels, crop conveyors, and the like, all of which aremechanically driven from a power source on the harvester vehicle. Thetable or platform is conventionally mounted on the vehicle such that theplatform can be raised and lowered selectively for transport of themachine and for selective cutting heights of the crop to be harvested.

mechanism to be operated in close proximity to the 0 ground withoutdamage to any vital components of the mechanism. I

Conventionally, it is known to provide counterbalancing means, such assprings, to aid in the irregular raising or lowering movements of thetable assembly during movement of the harvester over the ground, andproviding a table suspension system with flotation characteristic. inthe past, however, the counterbalancing means have been provided betweenthe frame of the vehicle and the platform, independently of the plat- 40form lowering or raising mechanism, including power lift cylinders.Thus, thedeflection and consequently the effectiveness of thecounterbalancing means considerably varied in accordance with theselected height of the table from the ground. The counterbalancingsprings are generally designed and positioned such between the frame andthe platform that optimum spring force is exerted when the platform isclose to the ground. The counterbalancing force of the springs,

however, rapidly decreases when the platform is raised from the ground,thus partially defeating the counterbalancing purpose.

As is known, the table assemblies are of substantial size and, asmentioned before, carry many structural components and drive mechanismsfor the components. Thus, obviously, a strong framework is required tocarry such heavy structure while the table must be pivotally supportedon the vehicle for movement towards or away from the ground. Hitherto,this required a plurality of lift and support arm and linkage systems,such as parallelograms, to maintain the pivotal movement of the tablewithin predetermined limits and to permit table movement in fore and aftdirection relative to the vehicle as well as in a vertical direction.

Furthermore, it is necessary, in many instances, to mount the drivecomponents of the table assembly towards one side of the platform. Thatside of the platform, therefore, will be heavier than the opposite side,

resulting in an unbalanced weight distribution. This has to beaccommodated for by the table lift and linkage arrangement, which cannotalways be effectively accomplished. Due to structural limitations, thetable lift and linkage arrangement cannot always accommodate theunbalanced weight distribution. Thus, in an elevated position, the tableassembly tends to tilt towards the improved flotation and levelingsystem for the table as- 10 heavier side.

In other instances, as is known, the table assemblies are equipped withtransversely shiftable crop conveyor means adapted to move the cut croptowards either end of the table for side delivery of windrows. Theresulting -weight transfer from one end of the table to the other byshifting of the conveyor means previously had likewise to beaccommodated for by proper adjustment of the lift arms or supportinglinkage which, similarly, cannot always be efiectively accomplished, orat best, is time consuming and requires special attention by theoperator of the machine.

The present invention provides an improved lift arm and linkage systemfor a table or-platform of a harvesting machine adapted to effectivelyovercome the above problems and, particularly, the problem concernedwith unbalanced weight distribution along the table or platform.

Accordingly, it is the primary object of the present invention toprovide improved lift arm and supporting means for mounting a tableplatform on an agricultural machine, including improved table platformcounterbalancing means and self-acting platform leveling means incase ofunbalanced weight distribution.

It is another object of the present. invention to provide acounterbalancing system-for a table platform of such construction thatthe counterbalancing force remains completely unaffected by the relativeoperating position of the platform and which permits independent liftingmovement of either end of the table in response to irregularities in theground contour.

Another object of the invention resides in the provision of a liftsystem for a table platform, including counterbalancing means in whichthe platform is supported only by the counterbalancing means when theplatform is in lowered operating position independently of anymechanical lifting means whereby the platform is able to freely floattofollow the contours of the ground.

Still another object of the present invention is to provide a suspensionsystem for the table platform of an agricultural machine, includingmeans to automatically maintain the table platform in a level and stableoperating position in response to unbalanced weight distribution alongthe table platform.

The above and other objects and novel features of the present inventionwill become more fully apparent by reference to the following detaileddescription in connection with the appended drawings.

The accompanying drawings illustrate a preferred embodiment of theinvention in which:

FIG. 1 is a fragmentary side elevation of the front portion of anagricultural machine having a table platform connected thereto by meansof a lift and suspension system constructed in accordance with thepresent invention, the table platform being schematically shown inlowered operating position;

FIG. 2 is a transverse cross-section through the front end of theagricultural vehicle facing in the direction of forward travel of thevehicle and in which portions at the right hand side have been omittedfor clarity;

FIG. 3 is an enlarged longitudinal cross-section along the center lineof the torsion bar arrangement shown in FIG. 2 and as seen in thedirection of the arrows 3-3 thereof; I I

.FIG. 4 is a fragmentary right hand side view of the stabilizer systemof the present invention illustratin the opposite side of the torsionbar linkage;

FIG. 5 is a transverse cross-section of the torsiori'bar arrangementshown in FIG. 2 and as seen in the direction of arrows 55;

FIG. 6 is a fragmentary rear view of a portion of the stabilizer systemshown in FIG. 2 and as seen in the direction of arrows 66; and

FIG. 7 is --a fragmentary cross section through the rocker arm pivotarrangement interconnected between the counterbalancing means and thelift arm cylinder in the lower portion of the system shown in FIG. 1 andas seen along line 7-7 thereof.

DETAILED DESCRIPTION OF THE INVENTION With continuous reference to thedrawings, FIGS. 1 and 2 schematically indicate a front end framestructure 10 of an agricultural harvesting machine such as a windrowerand which may be of any known construction. The harvesting machine isforwardly supported on traction wheels 12. The traction wheels 12 aresupported at the lower end of a drive mechanism housing 14, which ispart of the frame 10. The drive mechanism in the housing 14 is adaptedto rotate traction wheels 12 to propel the machine over the ground G.

I bifurcated bracket portion 36 of rocker arm 34 is Located in front offrame 10 and traction wheels 12 is a conventional header or tableassembly, only schematically indicated at 16, and in which the platform18 is adapted to be equipped with power driven crop gathering andworking means (not shown), as is common practice. The platform 18 inFIG. 1' is shown lower-mostoperating position relative to the ground-For selective lowering and raising of the platform 18 relative to groundG, the table assembly 16 is pivotally suspended from frame 10 by meansof oppositely disposed lower and upper suspension assemblies 20 and 22respectively. The pair of lower suspension assemblies 20 aresubstantially identical and one such assembly is provided at both sidesof the centerline of table assembly 16 as will be understood. Since bothlowergsuspension assemblies 20 are identical, it

will suffice to describe only one of the assemblies.

The lower suspension assemblies 20 are composed of a lower extendablelift arm 24 which may be a fluid cylinder having a reciprocating pistonrod 26 which is pivotally attached at 28 to platform 18. The rear end 30of lift arm cylinder 24 is pivotally attached by means of pivot pin 32tothe lower end of a rocker arm 34 which extends angularly upwardly fromthe lift cylinder 24. Rocker arm 34 extends below the lower forward endof the drive housing 14 and is provided intermediate its end with abifurcated bracket member 36 which extends in a direction normal to thelongitudinal axis of rocker arm 34 and upwardly therefrom.

provided at their ends with a bushing 46 in which the inner ends of thetrunnion pins 44 are journaled. Thus,

bracket 48 which has an upper flat surface 50 for abutment againstsurface 15 of drive housing 14 to thereby limit rotation of rocker arm34 in counterclockwise direction around pivot pin 32, as viewed in FIG.1, for a purpose to appear.

The opposite end of rocker arm 34 is pivotally connected at 52 to theouter end of a spring retainer 54 adapted to retain the lower end of atension spring 56.

Tension spring v56 is a longitudinally. coiled spring havingapredesigned spring characteristic adapted to exert maximum spring forcein the lower-most position of the table assembly 16, which isillustrated in FIG.-l. The upper end of spring 56, which extendsalongside drive housing 14, is secured to an adjustable retainer 58 Thetension spring 56 exerts a constant force on the rocker arm 34 to rotaterocker arm 34 around pivot 44 in a clockwise direction. The mass of theplatform 18- 'exerts a force to rotate rocker arm 34 around pivot 44 ina counterclockwise direction which is slightly greater than the force ofthe spring 56 until the stop member 48 abuts against surface 15 of drivehousing 14 as shown in FIG. 1. In the lowered position of table assembly16, the inactive liftcylinder 24 acts as a solid link between the table18 and the other end of rocker arm 34 to which the lift cylinder ispivotally attached by pivot pin 32. In the lowered position of tableassembly 16, close to the ground, springs 56 are at their maximum springforce capacity to provide opposite counterbalancing means for effectiveflotation of table assembly 16 in correspondence with the ground contourover which the machine travels. Thus, if the left 'side of tableassembly 16. which is illustrated in FIG. 1, should encounter anobstruction on the ground such as debris,

' and permit raising and lowering of the table assembly in stablecondition.

An upper suspension assembly 22 isprovided at the The right hand uppersuspension assembly 22a is similarly comprised of a lift arm 94 which isalso rigidly attached by means of bolts 96 to a similar opposite leftside of table assembly 16 as shown in FIG. 1, and a similar uppersuspension assembly 22a is provided at the right side as shown in FIG.4. The left side upper suspension assembly 22 will now first bedescribed in detail with reference to FIGS. 1 and 2.

The left upper suspension assembly 22 is comprised of a lift arm member66 which is boomerang shaped in plan view as shown, having one endrigidly secured by means of bolts 68 to the end of a bracket 70extending rearwardly from the upper end of table assembly 16. The otherend of lift arm 66, which extends rearwardly away from table assembly16, is attached to an adjustable link member 72. The other end ofadjustable link member 72 is pivotally connected to the free end of alever 74 which is positioned adjacent lift arm 66 in overlying angularlydisposed position thereto. It will be noted that lever 74 extendsangularly downwardly in relation to the upper end of lift arm 66 wherebyadjustable link member 72, which is normally rigid, provides aforce-transmitting connection between the upper end of lift arm 66 andthe free end of lever 74.

Lift arm 66 intermediate its ends but closer to its upper end isprovided with a welded-on bracket 7 member 76' which extends upwardlytherefrom for pivotal securement of lift arm 66 intermediate its ends tothe outer member 78 of a spherical bearing 80 for rotation therearound.The spherical bearing 80 is supported on the outer end of a transverserod member 82 which extends between opposite upper suspension assemblies22 and 22a respectively, in transverse direction to the line of travelof the machine.

The other end of lever 74 is secured to the outer end of longitudinaltransverse rod member 82 adjacent of and outwardly of spherical bearing80 by means of a clamping sleeve 84 which is splined to the outer end oftransverse rod member 82 and is held in retainment against sphericalbearing 80 by means of a lock ring 86.

Transverse rod member 82 comprises part of a stabilizer and drive shaftassembly 88 which is supported at opposite ends within side brackets 90secured to a cross beam member 92 which extends transversely betweenopposite drive housing 14 and forming a part of the frame assembly 10.The cross beam frame member 92, as seen in FIG. 2, extends in adjacentparallel position relative to stabilizer and drive shaft assembly 88.

With additional reference to FIG. 4 which illustrates the right handupper suspension assembly 22a (as seen in the direction of travel of themachine), it will be seen that the opposite outer end of transverse rodmember 82 is similarly supported for rotation within a similar bracket90 of the frame structure l0 and extends a distance outwardly therefrom.

bracket 70a extending from the opposite upper end of table assembly 16in the manner as shown in FIG. 1.

Right hand upper lift arm 94 is of straight longitudinalconfiguration incontrast to the boomerang shape of left hand lift arm 66. The other endof right hand upper lift arm 94 is similarly secured to the outer 7member 98 of a spherical bearing 100 for rotation. Bearing 100 issupported on the opposite outer end of transverse rod member 82 adjacentthe outside of supporting bracket 90.

Similarly, a lever 102 is provided having one end attached by means ofclamping sleeve 104 to the outer end of transverse rod member 82. Theclamping sleeve 104 is similarly splined to the outer end of rod member82 and is retained in longitudinal direction against spherical bearing100 by means of retaining ring 106.

' As seen in FIG. 4, lever 102 extends in angularly offset positionrelative to lift arm 94 and the free end of lever 102 is connected to arigid link member 108. The other end of rigid link member 108 isconnected to the right hand upper lift arm 94 at a selected pointintermediate the ends of the lift arm. Thus, the right hand upper liftarm 94 and right hand lever 102 are similarly interconnected by a rigidlink member in force-transmitting relationship.

As described, the opposite'upper suspension assemblies 22 and 22a atopposite sides of the table assembly 16, are interconnected bytransverse'rod member 82. Thus, upon relative raising or loweringmovement of table assembly 16 at either end or at both endssimultaneously the upper suspension assemblies 22 and 22a will be causedto rotate due to the rigid connection of the upper lift arms 66 and 94to the upper end of the table assembly. The pivotal movement of tableassembly 16 is translated by the respective upper lift arms 66 and 94into a rocking movement having the axis of the associated levers 74 and102 are non-rotatably secured to the respective outer ends of transverserod member 82 so that, upon rocking movement of the levers in eitherdirection, a rotational force will be exerted on transverse rod member82. i

Transverse rod member 82 in the present arrange ment defines a torsionbar adapted to maintain the plat- I form 18 of table assembly 16 in alevel horizontal position. As mentioned previously, the arrangement ofthe various components along the table platform 18 may be such that oneside of platform 18 is heavier than the other side of the platform.Although this is normally compensated for by variation in size of thepair of lift. cylinders 24, as previously mentioned, there is, in a"suspended or elevated position of the platform 18, a

tendency for the heavier side of the platform to drop relative to theother side. However, because of the torsional linkage arrangement atboth sides'of table assembly 16 (defined by the upper suspensionassemblies 22 and 22a and. interconnecting torsion bar 82), the platform18 of table assembly 16, at all times, will be maintained in horizontallevel position regardless of the weight unbalance along the platform 18,as will be more fully explained in the description of the operation ofthe device.

With more particular reference to FIGS. 2, 3, and 6, the stabilizer anddrive shaft assembly 88 further comprises a longitudinal tubular member110 disposed around a substantial portion of torsion bar 82. The tubularmember 110 is rotatable around torsion bar 82 and at one end issupported within a cylindrical adapter 112 which may be welded orotherwise secured to tubular member 110. Adapter 1 12 has a counterbore114 of larger diameter than tube 110 for axial extension over a sleevemember 116 through which the torsion bar 82 extends in freely rotatablerelationship. Adapter 112 is rotatable around sleeve member 116 by meansof a bearing assembly 118 and the outer end of adapter 1 12 is sealedagainst the sleeve support member 1 16 by means of a sealing assembly119. The sleeve support member 116 is non-rotatably supported within aflange 120 which is stationarily secured to frame bracket 90. Theadapter 112 at one end of tube 110 is provided to support a sheave,pulley or the like 122, for rotation therewith.

Tubular member 110 defines a drive shaft rotatable around torsion bar 82by means of a driven wheel such as a pulley or the like 124 disposed atthe inner end of tubular drive shaft 110. Pulley. 124 is similarlysupported on a cylindrical adapter 126 which is attached, as by weldingor the like, to the other end of tubular drive shaft 110. Similarly,adapter 126 has a counterbore 128 of larger diameter than the outerdiameter of As more particularly seen in FIG. 6, bracket portion 146 isintegral with a right angularly disposed plate member 150 which extendsacross the open space 93 and in lateral abutment with the side ofcrossbeam member 92 facing the drive shaft and torsion bar assembly 88.Plate member 150 of bracket assembly 144 is secured to both portions ofcrossbeam member 92 adjacent the space 93 by means of screws 152. Theplate member 150 is provided with a cut out or recess 154'disposed inplanar alignment with the pulley 124 to permit extension of the drivebelt from pulley 124 conjointly with the space 93 provided in crossbeammember 92.

To provide for lubrication of drive shaft bearings l 18 and 132, agrease fitting 156 is provided in tubular drive shaft 110 intermediateits ends whereby lubricant is permitted to be introduced into the radialspace between the torsion bar 82 and the interior of tubular drive shaft110 for outward flow towards drive shaft bearings 118 and 132.

It will be understood that pulley 124 is drivingly connected by means ofa drive belt (not shown) to a power transmission associated with thevehicle indicated by the frame structure 10. Similarly, pulley 122, atthe other end of tubular drive shaft l10, is drivingly con-' nected byany conventional means to the driven components (not shown) carried bythe table assembly 16. Thus, by application of driving power, tubulardrive shaft 110 is rotated for transfer of driving force from pulley 124to pulley 122 and subsequently to the driven components on tableassembly 16, as is known. The optubular drive shaft 110 for axialextension over a sleeve 1 support member 130. Adapter 126 is rotatablearound sleeve'support member 130 by means of a bearing assembly 132 andthe outer end of adapter 126 is sealed by means of sealing assembly 134.Similarly, sleeve support member 130 is non-rotatably secured within aflange member 136 and torsion bar 82 freely rotatably extends throughsleeve support member 130. t

' In order to maintain the exposed portion of the torsion bar 82, at theright side of the assembly in FIG. 2 and 3, in axial alignment, the endof torsion bar 82 inwardly of bracket member 90 is rotatably supportedwithin another sleeve support member 138 which is non -rotatably securedwithin a flange 140 attached to m; frame bracket 90. With particularreference to FIGS. 5 and 6, the outer end of tubular drive shaft 110, asdescribed above, is supported on sleeve support member 130 which isnonrotatably secured within the flange member 136. Flange member 136 isrigidly attached to a flange portion 142 of a bracket support assembly144 through which torsion bar 82 extends. Bracket support assemblyl44-extends rearwardly adjacent pulley 124 for attachment to the framecrossbeam member 92 of the vehicle. As seen in FIG. 2, the crossbeammember 92 of the frame of the vehicle is divided in the vicinity of thedrive pulley 124 to provide a space 93 to permit rearward extension of adrive belt (not shown) from the pulley 124. The top portion 146 ofbracket support assembly 144 is attached by means of bolts 148 to bothsections of crossbeam 'member 92 across the space 93.

posite coaxial bearing and support assemblies 1 12, 1 16, 126 and 130assure axial alignment of drive shaft 1 10 in concentric relationshiparound torsion bar 82. Tubular drive shaft 1 10, and its associatedsupports,- at the same time, provide axial alignment for torsion bar 82along a substantial portion of its length to counteract any bendingforces which may occur.

In operation, when the table assembly' 16 is to be elevated, theopposite lift cylinders 24 are actuated for extension of their pistonrod 26 to thereby swing table assembly 16 upwardly around the axis oftorsion bar 82 by means of the connecting upper lift arms 66 and 94-.

Conjoined rocking movement of upper lift arms 66 and 94 at opposite endsof torsion bar 82, by elevation of table assembly 16, causes rotation oftorsion bar 82 within tubular drive shaft and associatedsupport sleeves116, 130, and 138. Since both upper lift arms 66 and 94 are caused topivot at the same rate of rotational movement because of exertion of thesame lifting force at both ends of table assembly 16 by means ofopposite lift cylinders 24 (and when the table is in balanced weightcondition), torsion bar 82 will normally just be rotated without anytwisting effect. However, if one side of the table assembly 16 isheavier than the other side, the heavier side will tend to drop relativeto the other side of the tableassembly. This causes a Torsion bar 82 canbe pre-loaded in accordance with the weight distribution of tableassembly 16 by means of longitudinal adjustment of the adjustable linkmember 72 between upper lift arm 66 and lever 74 of the left hand uppersuspension assembly 22, as previously mentioned.

When the table assembly 16 is in lowered operating position, asillustrated in FIG. 1, the weight of the table assembly is resilientlysupported by the pair of counterbalancing spring assemblies 56 of theopposite lower suspension assemblies 20. Thus, when a depression orelevation on the ground is encountered, the table assembly 16 is enabledto float to permit close following of the contours of the ground,whereby the stabilizer means, (comprising torsion bar 82 and upper liftarm assemblies 22 and 22a), compensate for uneven weight distributionalong table assembly 16 to maintain table assembly 16 in equilibriumregardless of the weight distribution.

Thus, it will be seen from the foregoing description and with referenceto the attached drawings that the present invention provides improvedstabilizing means for the table assembly of an agricultural machine toaccommodate uneven weight distribution on the table assembly which iseffective to provide a counterbalancin g force in direct proportion tothe heavier load at one side of the table assembly relative to the otherside to thereby tend to maintain the table assembly at all times in alevel horizontal position.

The present stabilizer means includes a torsion bar and a pair of upperlift arm assemblies interconnected by lever meansto the opposite ends ofthe torsion bar so that any relative difference in pivotal movement ofthe upper lift arm assemblies in response to a transverse tiltingmovement of the table assembly towards one or the other side creates acounterbalancing force in opposite direction to maintain the tableassembly in a level horizontal position.

The present improved stabilizer system in conjunction with the lowersuspension assemblies, as herein described, provides improved stabilityfor the table assembly in either elevated or lowered position withoutaffecting in any way the desired floatability of the table assembly topermit close ground contour following when the table assembly is inoperating position.

Although the present invention has been described by way of a preferredembodiment, it will be understood that the particular embodiment hereindescribed is subject to various modifications in arrangement and detailsuch as come within known or customary practice known in the art towhich the invention pertains without departing from the essentialcharacteristic and spirit of the invention as defined by the appendedclaims.

What we claim is:

1. In an agricultural vehicle having a frame, at least one pair ofground engaging wheels supported on said frame, a platform pivotallymounted on said frame forwardly of said pair of wheels; said framehaving a supporting member extending transversely between said wheelsfor pivotal attachment of said platform thereto; a pair of extendablemembers for adjustable support of said platform to raise or lower saidplatform relative to the ground; a pair of counterbalancing means, eachcounterbalancing means being connected between said frame and one end ofa respective one of said extendable members; the improvement comprisinga pair of lift arms each having one end connected to said platform;torsional force-transmitting means operatively interconnecting the otherends of said pair of arms along an axis transverse to the longitudinalaxis of said vehicle; lever means secured to each end of said torsionalforcetransmitting means and a pair of link means interconnecting each ofsaid lever means with one of said lift arms such that when oneouter endof said platform is lowered relative to the other outer end, the arm atsaid one outer end causes rotation of said lever means associated withsaid one arm through connection of said link means to activate saidtorsional force-transmitting means so as to apply a rotating force inopposite direction in order to level said platform.

2. In an agricultural vehicle having a longitudinal axis comprising aframe structure having axially spaced ground supporting wheelsjournalled on a common transverse axis; an implement including anormally horizontally disposed platform elongated in a directiontransverse to the longitudinal axis of said vehicle; the improvementcomprising a pair of mounting elements connected to said platform atlongitudinally transversely spaced points to pivotally mount saidplatform to said frame structure for tilting movement of each outer endof said platform independently of the other end thereof about thelongitudinal axis of said vehicle; a pair of counterbalancing elementscarried by said frame structure and operatively connected atlongitudinally transversely spaced points to said platform forfloatingly supporting said platform; link and forcetransmitting meansoperatively connected between said platform and said frame structure forbodily raising and lowering said platform relative to said wheels; saidmeans including an extendable link member spaced towards each side ofsaid longitudinal axis pivotally secured at one end of said platform; apivotal rocker arm spaced towards each side of said longitudinal axissecured to said frame for pivotal movement thereon;

said pivotal rocker arms each interconnecting the other end of one ofsaid extendable link members with one of said counterbalancing elements;a pair of arms at opposite sides of said longitudinal axis having oneend rigidly connected to said platform; a transverse rod member disposedrearwardly of said platform in parallel position to the axis of saidwheels; the opposite outer ends of said transverse rod member beingdisposed within said frame structure for relative rotation therein; alever having one end thereof mounted at each end of said transverse rodmember, the other end of each of said levers connected to a respectivelink member, the other end of each of said link members being connectedto the other end of a respective one of said arms; said transverse rodmember comprising a torsion bar and permitting said torsion bar uponrelative raising or lower movement of either one outer end of saidplatform to exert a force in opposite directions by means of saidrotation of the respective one of arm, lever and link member to levelsaid one outer end relative to the other outer end of said platform.

3. In an agricultural vehicle having a frame, at least one pair ofground engaging wheels supported on said frame and a platform pivotallymounted on said frame forwardly of said pair of wheels; a floatation andlift posite ends of a stabilizer assembly supported within said framealong a direction transverse to the direction of travel of said vehicle;counterbalancing means operatively connected between said frame and saidplatform; extendable lifting means having one end con-- nected to saidplatform, and rocking lever means having opposite ends pivotallyconnected to the free end of said counterbalancing means and to theother end of said lifting means respectively and being pivotallysupported for rocking movement on said frame; said stabilizer assemblycomprising a torsion bar maintaining said platform in a level positionupon raising or lower movement of either outer end of said platformrelative to the ground.

4. In an agricultural vehicle comprising a wheeled frame adapted forground travel; a platform positioned forwardly of said frame andextending in a transverse direction thereto; a support structure forraising and lowering said platform relative to said frame and saidground, said support structure comprising an extendable lift memberhaving one end pivotally connected to said frame and an opposite endpivotally connected to said platform; resilient counterbalancing meansconnected to said frame for extension between said frame and saidextendable lift member; said resilient counterbalancing meansmaintaining opposite ends of said platform in adjustably loweredposition on said ground; a' pair of upper lift arm and lever assembliesconnected to said platform; each of said lift arms being rigidlyconnected to said platform; means connecting each of the other ends ofsaid lift arms to one end of a lever associated therewith; alongitudinal stabilizer assembly supported by said frame in transversedirection of travel of said vehicle; each of said lift arm and leverassemblies being connected to a respective outer end of said stabilizerassembly so that, when one of said lift arm and lever assemblies isactuated for rocking movement due to unilateral movement of saidplatform, said stabilizer assembly will be effective to exert a force inl nected to said frame, and a rocker arm pivotally conopposite directionto the unilateral movement of said platform. a

5. The support structure, as defined in claim 4, further characterizedby the provision of rocking means pivotally supported on said frame;said rocking means comprising a longitudinal member having one endpivotally connected to the free end of the resilient counterbalancingmeans and the other end to one end of said extendable lift member; saidpivotal connection of said rocking means to said frame being locatedintermediate the ends of said longitudinal member to cause rockingmovement of said longitudinal member upon exertion of a force at eitherend of said member.

6. The support structure, as defined in claim 5, characterized by theprovision of stop means at one end of said longitudinal member'of saidrocking means for cooperating with abutment means on said frame to limitrocking movement of said direction.

7. In an agricultural vehicle comprising a wheeled frame adapted forground travel; a platform disposed forwardly of said frame and extendingtransverse to the direction of travel of said vehicle; a pair oflaterally spaced suspension assemblies carried by said frame at oppositesides of said platform, each suspension assembly comprising a lower liftmember having arearward end pivotally connected to said frame and aforward end pivotally connected to said platform; a resilientcounterbalancing means having one end conrocking means in one nectedintermediate its ends to said frame; one end of said rocker arm beingpivotally connected to the rear end of said lift member and the oppositeend of said rocker arm being pivotally connected to the other end ofsaid resilient counterbalancing means; a pair of upper lift arm andlever assemblies disposed between said platform and said frame, saidlift arms being rigidly connected'to said platform, each of said liftarm and lever assemblies including an intermediate link member for forcetransmitting connection of adjacent ends of one lift arm and one leverof each of said lift arm and lever assemblies; and a longitudinal rodmember rotatably supported within said frame in transverse direction oftravel of said vehicle; each of said levers of said lift arm and leverassemblies being secured to one end of said longitudinal rod member sothat, upon pivotal movement of said platform relative to said frame,said lift arm and lever assemblies will be caused to rock around theaxis of said longitudinal rod member in either clockwise orcounterclockwise direction, conjointly or separately, said longitudinalrod member providing a rotational energy-storing capacity effective tocounteract individual rotational rocking movement of either lift arm andlever assembly in. either direction of rotation.

8. The suspension assembly, as defined in claim 7, characterized in thatone end of said rocker arm at the rear end of said lower lift member isprovided with stop means for co-acting engagement against said frame inthe'lowered position of said platform to thereby limit furtherrotational movement of said rocker arm in one direction.

9. The suspension assembly as defined in claim 7 characterized in thatsaid longitudinal rod member comprises a torsion bar; said lever of eachof said pair of upper lift arm and lever assemblies being rigidlyconnected to a respective end of said torsion bar so that, upon rockingmovement of said lift arm and lever assemblies in either direction, saidtorsion bar will be loaded to exert a force in the correspondingopposite direction to thereby maintain said platform in a level positionrelative to said frame.

10. The suspension assembly, as defined in claim 9, furthercharacterized in that one of said intermediate link membersinterconnecting one 'of said lift arms with one of said levers isprovided with means for longitudinal'length adjustment whereby said onelever can be rotated relative to said one lift arm and independently ofthe other lever and lift arm assembly to preload said torsion bar. 1

11. In an agricultural vehicle comprising a wheeled frame adapted forground travel along a longitudinal axis; a platform positioned forwardlyof said frame and extending transversely to said longitudinal axis, saidplatform having crop gathering means supported thereon; a pair oflaterally spaced support structures on oppositesides of saidlongitudinal axis, each of said support structures comprising a lowerextendable lift member having a forward end pivotally connectedto saidplatform; a longitudinal resilient member having one end connected tosaid frame; a rocker arm pivotally interconnecting the other end of saidlongitu-' dinal resilient member with the other end of said lower liftmember; said rocker arm being pivotally supported on said frameintermediate its ends; a pair of upper lift assemblies, one at each sideof said frame; a transverse torsion bar rotatively carried by said framefor extension between said upper lift assemblies; said upper liftassemblies comprising a pair of levers, one of said levers non-rotatablyconnected to one end of said torsion bar and the other of said leversnon-rotatably connected to the opposite end of said torsion bar; a pairof lift arms each having one end rigidly connected tosaid platform, theother end of each of said lift arms being rotatably connected toopposite ends of said torsion bar conjointly with said pair of levers; apair of rigid link members; one link member pivotally connecting one ofsaid levers to one of said lift arms and the other of said link memberspivotally connecting the other of said levers to the other of said liftarms; said pair of link 4

1. In an agricultural vehicle having a frame, at least one pair ofground engaging wheels supported on said frame, a platform pivotallymounted on said frame forwardly of said pair of wheels; said framehaving a supporting member extending transversely between said wheelsfor pivotal attachment of said platform thereto; a pair of extendablemembers for adjustable support of said platform to raise or lower saidplatform relative to the ground; a pair of counterbalancing means, eachcounterbalancing means being connected between said frame and one end ofa respective one of said extendable members; the improvement comprisinga pair of lift arms each having one end connected to said platform;torsional force-transmitting means operatively interconnecting the otherends of said pair of arms along an axis transverse to the longitudinalaxis of said vehicle; lever meanS secured to each end of said torsionalforce-transmitting means and a pair of link means interconnecting eachof said lever means with one of said lift arms such that when one outerend of said platform is lowered relative to the other outer end, the armat said one outer end causes rotation of said lever means associatedwith said one arm through connection of said link means to activate saidtorsional force-transmitting means so as to apply a rotating force inopposite direction in order to level said platform.
 2. In anagricultural vehicle having a longitudinal axis comprising a framestructure having axially spaced ground supporting wheels journalled on acommon transverse axis; an implement including a normally horizontallydisposed platform elongated in a direction transverse to thelongitudinal axis of said vehicle; the improvement comprising a pair ofmounting elements connected to said platform at longitudinallytransversely spaced points to pivotally mount said platform to saidframe structure for tilting movement of each outer end of said platformindependently of the other end thereof about the longitudinal axis ofsaid vehicle; a pair of counterbalancing elements carried by said framestructure and operatively connected at longitudinally transverselyspaced points to said platform for floatingly supporting said platform;link and force-transmitting means operatively connected between saidplatform and said frame structure for bodily raising and lowering saidplatform relative to said wheels; said means including an extendablelink member spaced towards each side of said longitudinal axis pivotallysecured at one end of said platform; a pivotal rocker arm spaced towardseach side of said longitudinal axis secured to said frame for pivotalmovement thereon; said pivotal rocker arms each interconnecting theother end of one of said extendable link members with one of saidcounterbalancing elements; a pair of arms at opposite sides of saidlongitudinal axis having one end rigidly connected to said platform; atransverse rod member disposed rearwardly of said platform in parallelposition to the axis of said wheels; the opposite outer ends of saidtransverse rod member being disposed within said frame structure forrelative rotation therein; a lever having one end thereof mounted ateach end of said transverse rod member, the other end of each of saidlevers connected to a respective link member, the other end of each ofsaid link members being connected to the other end of a respective oneof said arms; said transverse rod member comprising a torsion bar andpermitting said torsion bar upon relative raising or lower movement ofeither one outer end of said platform to exert a force in oppositedirections by means of said rotation of the respective one of arm, leverand link member to level said one outer end relative to the other outerend of said platform.
 3. In an agricultural vehicle having a frame, atleast one pair of ground engaging wheels supported on said frame and aplatform pivotally mounted on said frame forwardly of said pair ofwheels; a floatation and lift suspension system connecting said platformwith said frame, the improvement comprising: a pair of link andinterconnecting lever assemblies connected between said frame and saidplatform; each of said assemblies including a first element fixed tosaid platform, a second element pivotally secured to said first element,and a link member pivotally connected between said first and secondelement; each of said second elements being further interconnected oneto each other at opposite ends of a stabilizer assembly supported withinsaid frame along a direction transverse to the direction of travel ofsaid vehicle; counterbalancing means operatively connected between saidframe and said platform; extendable lifting means having one endconnected to said platform, and rocking lever means having opposite endspivotally connected to the free end of said counterbalancing means andto the other end of said liftiNg means respectively and being pivotallysupported for rocking movement on said frame; said stabilizer assemblycomprising a torsion bar maintaining said platform in a level positionupon raising or lowering movement of either outer end of said platformrelative to the ground.
 4. In an agricultural vehicle comprising awheeled frame adapted for ground travel; a platform positioned forwardlyof said frame and extending in a transverse direction thereto; a supportstructure for raising and lowering said platform relative to said frameand said ground, said support structure comprising an extendable liftmember having one end pivotally connected to said frame and an oppositeend pivotally connected to said platform; resilient counterbalancingmeans connected to said frame for extension between said frame and saidextendable lift member; said resilient counterbalancing meansmaintaining opposite ends of said platform in adjustably loweredposition on said ground; a pair of upper lift arm and lever assembliesconnected to said platform; each of said lift arms being rigidlyconnected to said platform; means connecting each of the other ends ofsaid lift arms to one end of a lever associated therewith; alongitudinal stabilizer assembly supported by said frame in transversedirection of travel of said vehicle; each of said lift arm and leverassemblies being connected to a respective outer end of said stabilizerassembly so that, when one of said lift arm and lever assemblies isactuated for rocking movement due to unilateral movement of saidplatform, said stabilizer assembly will be effective to exert a force inopposite direction to the unilateral movement of said platform.
 5. Thesupport structure, as defined in claim 4, further characterized by theprovision of rocking means pivotally supported on said frame; saidrocking means comprising a longitudinal member having one end pivotallyconnected to the free end of the resilient counterbalancing means andthe other end to one end of said extendable lift member; said pivotalconnection of said rocking means to said frame being locatedintermediate the ends of said longitudinal member to cause rockingmovement of said longitudinal member upon exertion of a force at eitherend of said member.
 6. The support structure, as defined in claim 5,characterized by the provision of stop means at one end of saidlongitudinal member of said rocking means for cooperating with abutmentmeans on said frame to limit rocking movement of said rocking means inone direction.
 7. In an agricultural vehicle comprising a wheeled frameadapted for ground travel; a platform disposed forwardly of said frameand extending transverse to the direction of travel of said vehicle; apair of laterally spaced suspension assemblies carried by said frame atopposite sides of said platform, each suspension assembly comprising alower lift member having a rearward end pivotally connected to saidframe and a forward end pivotally connected to said platform; aresilient counterbalancing means having one end connected to said frame,and a rocker arm pivotally connected intermediate its ends to saidframe; one end of said rocker arm being pivotally connected to the rearend of said lift member and the opposite end of said rocker arm beingpivotally connected to the other end of said resilient counterbalancingmeans; a pair of upper lift arm and lever assemblies disposed betweensaid platform and said frame, said lift arms being rigidly connected tosaid platform, each of said lift arm and lever assemblies including anintermediate link member for force transmitting connection of adjacentends of one lift arm and one lever of each of said lift arm and leverassemblies; and a longitudinal rod member rotatably supported withinsaid frame in transverse direction of travel of said vehicle; each ofsaid levers of said lift arm and lever assemblies being secured to oneend of said longitudinal rod member so that, upon pivotal movement ofsaid platform relative to said fraMe, said lift arm and lever assemblieswill be caused to rock around the axis of said longitudinal rod memberin either clockwise or counterclockwise direction, conjointly orseparately, said longitudinal rod member providing a rotationalenergy-storing capacity effective to counteract individual rotationalrocking movement of either lift arm and lever assembly in eitherdirection of rotation.
 8. The suspension assembly, as defined in claim7, characterized in that one end of said rocker arm at the rear end ofsaid lower lift member is provided with stop means for co-actingengagement against said frame in the lowered position of said platformto thereby limit further rotational movement of said rocker arm in onedirection.
 9. The suspension assembly, as defined in claim 7,characterized in that said longitudinal rod member comprises a torsionbar; said lever of each of said pair of upper lift arm and leverassemblies being rigidly connected to a respective end of said torsionbar so that, upon rocking movement of said lift arm and lever assembliesin either direction, said torsion bar will be loaded to exert a force inthe corresponding opposite direction to thereby maintain said platformin a level position relative to said frame.
 10. The suspension assembly,as defined in claim 9, further characterized in that one of saidintermediate link members interconnecting one of said lift arms with oneof said levers is provided with means for longitudinal length adjustmentwhereby said one lever can be rotated relative to said one lift arm andindependently of the other lever and lift arm assembly to preload saidtorsion bar.
 11. In an agricultural vehicle comprising a wheeled frameadapted for ground travel along a longitudinal axis; a platformpositioned forwardly of said frame and extending transversely to saidlongitudinal axis, said platform having crop gathering means supportedthereon; a pair of laterally spaced support structures on opposite sidesof said longitudinal axis, each of said support structures comprising alower extendable lift member having a forward end pivotally connected tosaid platform; a longitudinal resilient member having one end connectedto said frame; a rocker arm pivotally interconnecting the other end ofsaid longitudinal resilient member with the other end of said lower liftmember; said rocker arm being pivotally supported on said frameintermediate its ends; a pair of upper lift assemblies, one at each sideof said frame; a transverse torsion bar rotatively carried by said framefor extension between said upper lift assemblies; said upper liftassemblies comprising a pair of levers, one of said levers non-rotatablyconnected to one end of said torsion bar and the other of said leversnon-rotatably connected to the opposite end of said torsion bar; a pairof lift arms each having one end rigidly connected to said platform, theother end of each of said lift arms being rotatably connected toopposite ends of said torsion bar conjointly with said pair of levers; apair of rigid link members; one link member pivotally connecting one ofsaid levers to one of said lift arms and the other of said link memberspivotally connecting the other of said levers to the other of said liftarms; said pair of link members maintaining a predeterminedforce-transmitting relationship of said pair of levers relative to saidpair of lift arms and causing rocking of said levers upon respectivepivotal movement of said lift arms.
 12. The support structure as definedin claim 11, characterized by one of said link members being adjustablein length to selectively vary the torque characteristic of said torsionbar.